Heat Treatment Deformation and Prevention of Precision Mold
Generally speaking, the following methods can be taken to prevent heat treatment deformation of precision and complex molds.
1> Reasonable material selection. For precision and complex molds, micro-deformation mold steels with good materials (such as air quenching steels) should be selected. For mold steels with severe carbide segregation, reasonable forging and quenching and tempering heat treatment should be carried out. For larger and unforgeable mold steels, solid solution double refinement heat treatment can be carried out.
2> The design of the mold structure should be reasonable, the thickness should not be too disparate, and the shape should be symmetrical. For the mold with large deformation, the deformation law should be mastered, and the machining allowance should be reserved. For large, precise and complex molds, a combined structure can be used.
3> Pre-heat treatment is required for precision and complex molds to eliminate residual stress generated during machining.
4> Reasonably select the heating temperature and control the heating speed. For precision and complex molds, slow heating, preheating and other balanced heating methods can be adopted to reduce the heat treatment deformation of the mold.
5> Under the premise of ensuring the hardness of the mold, try to use pre-cooling, graded cooling quenching or warm quenching process.
6> For precision and complex molds, if conditions permit, vacuum heating quenching and cryogenic treatment after quenching should be used as much as possible.
7> For some precision and complex molds, pre-heat treatment, aging heat treatment, quenching and tempering nitriding heat treatment can be used to control the precision of the mold.
Finally, correct heat treatment process operation (such as hole plugging, hole binding, mechanical fixation, appropriate heating method, correct choice of mold cooling direction and movement direction in cooling medium, etc.) and reasonable tempering heat treatment process are also effective measures to reduce the deformation of precision and complex molds.
